1. Field of the Invention
The present invention relates to devices for indicating efficiency of fuel consumption in an internal combustion engine, and in particular in automotive vehicles.
2. Description of the Prior Art
Various sophisticated devices are currently available for indicating efficiency of fuel consumption in an internal combustion engine. Some devices are microprocessor based while other devices employ inordinately complex mechanisms to signal the efficiency of operation of an automotive vehicle powered by an internal combustion engine.
Conventional devices utilize as an input the pressure change in the vacuum manifold of an internal combustion engine which varies with the rate of fuel consumption with respect to engine speed. That is, while an internal combustion engine operates, the vacuum in the vacuum manifold decreases with increased fuel consumption for a given engine speed. Conversely, the vacuum increases in the vacuum manifold with a reduction in rate of fuel consumption for a given engine speed. In conventional devices this information is transformed to signals in an illuminated display to indicate economical, fair or wasteful operation, respectively, of an internal combustion engine. Conventional devices of this type at the very minimum involve transistorized driver circuits, gear mechanisms and other inordinately complex arrangements to accomplish the function of producing a visible display in which green, yellow and red indicators are employed to signify the vacuum condition in the vacuum manifold. One such conventional device is marketed as the Micronta fuel economy monitor by Radio Shack Company.